1. Field of the Invention
The invention concerns a device for providing columns of material in the ground, in particular packed material columns or drains.
2. Description of the Related Art
A comparable device is basically known from DE 22 60 473 C2. This includes a lifting device in the form of a movable crane. The lifting device serves for manipulating a conveyor system for constructing columns of material, which is comprised of a deep jolt ramming machine or another type of forward thrust head and a material conveyance conduit. With the help of the forward thrust head first a borehole is formed downwardly and this is subsequently filled with material. Depending upon the task at hand, the construction can be formed or configured in various ways. For production of drains, the material is loosely filled, so that a comparatively large porous space remains between the material particles. On the other hand a strongly compacted construction can be achieved, wherein the materials is strongly, and with sideways compression, packed.
In each case the fill material is supplied from above via the material conveyance tube or conduit wherein the entire conveyance system, that is, inclusive of the material conveyance conduit, is placed under positive pressurization, on the one hand to prevent penetration of water or earth material into the hollow space excavated by the boring or tunneling unit comprised of the material conveyance conduit and the forward thrust head, and on the other hand, to assure an emission of material underground.
The filling material is provided to the conveyor system in a charge-wise manner by means of a container and, more particularly, by feeding at the upper end of the material conveyor conduit. For manipulating of the container a rope or cable winch is provided, which is provided on the cantilevered beam of the lifting device in a known manner. Therewith it is possible, on other one hand, to set the container on the ground in order that it, while there, can be filled with available material. On other hand it can be lifted to the upper end of the material conveyor conduit, in order to feed or charge this with fill material.
In accordance with a further already in use development of the above-described device, a so-called Makler or rigging is used in place of the crane. Here we refer to a vertical mast, upon which a sled is moveably mounted, guided upon guide rails. The sled serves for manipulation of a transport system of the category discussed above.
The Makler further carries on its upper end a cantilever beam provided with a rope winch for manipulating the container. Makler and cantilever beam thus together form one constructive unit.
The manipulation of the conveyor system on the one hand and the container on the other hand are possible independently of each other. So the sled, and therewith the ramming machine, can be moved up and down in steps of approximately 0.5 m to 1.0 m. During the respective upwards movement fill material is emitted from the tip of the ramming machine. During the respective subsequent downward movement the material is packed sideways and also partially towards downwards into the ground. In this manner the so-called compact columns are formed.
Independent of the movement of the boring or sinking unit and the sled with charging lock or lock, the rope or cable winch is used to respectively lower the container to the ground, fill it with material and subsequently raise it again.
For charging the supply system with fill material it is necessary that the sled be halted so that the container can be docked to the supply conduit and be emptied. It is thus necessary that the jolt-ramming machine be halted at intervals, in order that the respective charge of material can be introduced. In the entirely conventional case a 10 m long gravel column with a column diameter of 0.8 m would require a gravel volume of 5 m.sup.3. Considering a useable volume of the container in the order of approximately 1 m.sup.3 there would thus be a requirement for five charges, which would lead to the necessary frequent interruptions in the production process.